<p> Synthetic methods for the preparation of 2,7-dimethoxy-1-naphthoic acid are presented. The selective reduction of this acid with sodium in liquid ammonia to give 1,4-dihydronaphthoic acid is described.</p> <p> The selective Birch reduction of 2,7-dimethoxynaphthalene to 1,4-dihydro-2,7-dimethoxynaphthalene has been accomplished. 2,7-Dimethoxy-3- isopropylnaphthalene was converted to 3-keto-12-methoxy-10-carbomethoxy-13-isopropylperhydrophenanthra-4,8,11,13-tetraene via, 1,2,3,4-tertrahydro-7-methoxy-6-isopropyl-1-carbomethoxynaphthalen-2-one. The transformation of 3-keto-12-methoxy-10-carbomethoxy-13-isopropylperhydrophenanthra-4,8,11,13- tetraene to methyl O-methyl-11-desoxycarnosate via methylation, thioketalisation, desulphurisation and hydrogenation is also described.</p> / Thesis / Doctor of Philosophy (PhD)

No description available.

This research report investigated the ruthenium-catalyzed hydrogenation of aqueous sodium bicarbonate. Subjects of the investigation included: the "blank" effect of the 316 stainless steel reactor in the batch mode; the catalytic activities at 150°C for unsupported ruthenium, including ruthenium purge and the metal produced from the in situ reduction of RuCl3·1-3H2O and Ru(IV)O2·H2O; the catalytic activities at 150°C for supported ruthenium including 4.05% w/w ruthenium on alumina, 5.25 and 20.85%w/w ruthenium on molecular sieve SK-41 (ammonium - substituted Y-type), 3.34 and 17.48% w/w ruthenium on SK-41 (prepared by the in situ reduction of the RuCl3·1-3H2O exchange sieve); orders of reaction rate with respect to hydrogen, bicarbonate, and catalyst at 150°C; activity as a function of temperature; and susceptibility to deactivation. The reaction appears to be zero order in both hydrogen and bicarbonate and first order in catalyst at 150°C in the concentration ranges examined; saturation of an assumed limited number of active catalyst sites is assumed to cause the observed zero orders. Conversion was negligible below 150°C, and optimum in the 150°C-200°C range, with product distribution at 150°C heavily favoring methane; e.g. 99% v/v. The stainless steel reactor was found not to catalyze the reaction at 150°C during a two hour reaction. Catalytic activity for unsupported ruthenium paralleled metal surface area (as determined by BET adsorption), while the inverse was found to be true for sieve-supported metal; mass transfer impedance and electronic effects are assumed to be contributing factors. The reaction on alumina-supported ruthenium produced an undesirable white coating, composition as yet undetermined, which strongly adhered to the support and to the reactor walls. Although the reaction investigated is even more exothermic than the Fischer-Tropsch production of methane, and the ruthenium catalyst was also found to be subject to deactivation, the reaction of interest may have an economic advantage over the Fischer-Tropsch synthesis, in that it is less expensive to decompose a bicarbonate species using hydration energy and then hydrogenate directly, then to thermally decompose the ore and hydrogenate the CO2 produced.

No description available.

Copper oxide supported on alumina (CuO/Al2O3), silica (CuO/SiO2) and chromia (CuO/Cr2O3) have been synthesized and characterized. These catalysts were characterized using XRD, SEM, TEM, ICP, BET surface area and pore volume, TPR, TPD, TGA-DSC and IR. The hydrogenation of octanal using these catalysts was investigated; however, the primary focus of the project was the influence of water on the reaction and the catalysts. The initial study using CuO/Al2O3 showed that the optimum operating conditions for subsequent catalytic testing was 160 °C and a hydrogen to aldehyde ratio of two. Under these conditions, a conversion of 99 % and selectivity to octanol of 97 % was achieved. Further catalytic testing, using CuO/Al2O3 and CuO/Cr2O3, was carried out by introducing water-spiked feed into the reaction system after steady state was reached using fresh feed. Based on literature, it was initially expected that the presence of water would cause catalyst poisoning and subsequently catalyst deactivation. However, contrary to the expectation, the presence of water did not influence the activity of these two catalysts. Furthermore, the selectivity to octanol increased to 98.5 % when CuO/Al2O3 was used for the reaction, whilst a minor change in the selectivity to octanol (0.5 %) was obtained when CuO/Cr2O3 was used. The interaction of the water with the surface hydroxyls on alumina is most likely the reason for the increase in the selectivity to octanol when using CuO/Al2O3. In contrast to the other two catalysts, the reaction over CuO/SiO2 showed a steady decrease in both the conversion of octanal and the selectivity to octanol with time-onstream when using fresh feed. After 55 hours on stream, the conversion reached 22 %, (from an initial 95 %) whilst the selectivity to octanol reached 89 % (from an initial 98 %). This decline in the conversion and selectivity to octanol was possibly due in part, to the low isoelectric point of silica, with mechanical failure being the major contributing factor to the catalyst’s deactivation. The decrease in the BET surface area and the presence of smaller particles in the SEM image, confirmed that mechanical failure occurred. Since steady state was not reached and deactivation occurred, the reaction over CuO/SiO2 was also carried out using water-spiked feed. The conversion of octanal was seen to gradually decrease to 73 % after 55 hours on stream, whilst the selectivity to octanol remained unchanged at 98 % for the duration of the reaction. This showed the beneficial effect of the presence of water by slowing down the decline in catalytic activity and maintaining the selectivity to octanol. The improved selectivity obtained in the presence of water was attributed to its interaction with the silica surface hydroxyls. Since octanal conversion continued to decrease, it indicated that mechanical failure was the primary cause in the loss of catalytic activity. The used catalysts were characterized using XRD, SEM, EDS composition scanning, TEM, BET surface area and pore volume, TGA-DSC and IR. The catalysts used for the reaction with the fresh feed and the water-spiked feed were characterized and compared. Except for the deactivation of CuO/SiO2, the characterization of these catalysts showed that the presence of water did not negatively impact the make-up of the catalyst. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2010.

Diimide generated from the hydrazine/hydrogen peroxide/catalyst system can be used to hydrogenate unsaturated polymers in latex form. As an economical and environmentally benign alternative to the commercial processes based on hydrogen/transition metal catalysts, this method is of special interest to industry. This thesis provides a detailed description of the diimide hydrogenation process. Reaction kinetics, catalysts and gel formation mechanism have been investigated. <br /> <br /> Four main reactions and a mass transfer process form three parallel processes in this system: diimide is generated at the interface of the latex particles; diimide diffuses into the organic phase to saturate carbon-carbon double bonds; diimide may be consumed at the interface by hydrogen peroxide, and may also be consumed by the disproportionation reaction in the organic phase. The two side reactions contribute to the low hydrogenation efficiency of hydrogen peroxide. Slowing down hydrogen peroxide addition and using stable interfacial catalysts may totally suppress the side reaction in the aqueous phase. The actual catalytic activity of metal ions in the latex depends on the hydrogen peroxide concentration and the addition procedure of reactants. Cupric ion provides better selectivity for hydrogenation than ferric ion and silver ion do. Boric acid as a promoter provides improved selectivity for hydrogenation and faster diimide generation rate. The side reaction in the rubber phase results in low efficiency and gel formation. The rate constants of the four reactions in this system are estimated. <br /> <br />It is shown that the hydrogenation of nitrile rubber latex with an average particle diameter of 72 nm is mainly a reaction-controlled process. Diimide diffusion presents limitation upon hydrogenation at high hydrogenation degree range. Antioxidants can not effectively inhibit gel formation during hydrogenation. Hydrogenation of a core-shell latex with NBR as the shell layer should be able to achieve a higher efficiency, a higher degree of hydrogenation and a lower level of crosslinking.

No description available.

Doctor of Philosophy / Department of Chemical Engineering / Peter H. Pfromm / Characterization of the interactions of hydrogen with catalytic metal surfaces and the mass transfer processes involved in heterogeneous catalysis are important for catalyst development. Although a range of technologies for studying catalytic surfaces exists, much of it relies on high-vacuum conditions that preclude in-situ research. In contrast, atomic force microscopy (AFM) provides an opportunity for direct observation of surfaces under or near actual reaction conditions. Tapping-mode AFM was explored here because it expands AFM beyond the usual topographic information toward speciation and other more subtle surface information. This work describes using phase-angle data from tapping-mode AFM to follow the interactions of hydrogen with palladium. Both gas-solid and liquid-solid interfaces were studied. Real-time AFM phase-angle data allowed for the observation of multiphase mass transfer to and from the surface of palladium at atmospheric pressure and room temperature without the need for complex sample preparation. The AFM observations were quantitatively benchmarked against and confirm mass transfer predictions based on bulk hydrogen diffusion estimates. Additionally, they support recent studies that demonstrate the existence of multiple hydrogen states during interactions with palladium surfaces.

This thesis focuses on the mechanistic investigation of catalytic carbon-carbon σ-bond hydrogenation of hydrocarbons using water as the convenient hydrogen source under neutral conditions by group 9 metalloporphyrins M(por)X. [With diagram] / The benzylic carbon-carbon bond of [2.2]paracyclophane (PCP) was catalytically hydrogenated to give 4,4’-dimethylbibenzyl up to 98% yield using water with 10 mol% M(ttp)X pre-catalyst (ttp = 5,10,15,20-tetratolylporphyrinato dianion, M = Rhᴵᴵᴵ and Irᴵᴵᴵ, X = Me, Bn and ⁱPr) at 200°C in C₆D₆. Deuterium labeling experiments using D₂O supported water as the hydrogen source. Preliminary screening with Coᴵᴵ(ttp) catalyst in polar DMF solvent at 220°C also yielded the hydrogenation product selectively. The role of DMF is proposed to promote the hydrolysis of cobalt(III) porphyrin benzyl intermediates and increase the solubility of H₂O.[With diagram] / Kinetic studies on the stoichiometric benzylic CCA of PCP with Rhᴵᴵ(tmp) metalloradical (tmp = 5,10,15,20-tetramesitylporphyrinato dianion) gave the rate law as rate = k[Rhᴵᴵ(tmp)]²[PCP]. The 2ⁿᵈ order dependence on Rhᴵᴵ(tmp) radical suggests a bi-metalloradical CCA mechanism via a four-centered transition state. [With diagram] / In the iridium catalyzed system, Irᴵᴵᴵ(ttp)H was found to have promoting role in the hydrogenation process. The bi-molecular reductive elimination between Irᴵᴵᴵ(ttp)H and the CCA intermediates speeded up the hydrogenation process. It is estimated that this process gave the hydrogenated alkyl fragment 3 times faster than hydrolysis of the CCA intermediates. [With diagram] / 本論文主要探討在中性反應條件下，利用水作為一個方便的氫來源，以第9族金屬卟啉，M(por)X，催化碳氫化合物中的碳碳單鍵加氫反應的反應機制。 / 在200°C及溶有10 mol% M(ttp)X (M = Rhᴵᴵᴵ 和 Irᴵᴵᴵ，X = Me，Bn和ⁱPr) 預催化劑的氘代苯中，利用水把[2.2]二聚對二甲苯的苄基碳碳鍵進行催化加氫，生成高達98%的4,4’-二甲基聯苄(下稱PCP)。利用氘代水的氘標記實驗支持了氫的來源為水。另一方面，經過以Coᴵᴵ(ttp)催化劑進行了初步篩選後，能在220°C及DMF極性溶濟中使加氫產物選擇性地生成。DMF的作用被提議為促進鈷卟啉苄基的水解及增加了水的溶解度。 / 在進行了Rhᴵᴵ(tmp)與PCP的當量苄基碳碳鍵活化動力學實驗後，得出速率方程rate = k[Rhᴵᴵ(tmp)]²[PCP]。Rhᴵᴵ(tmp)的二級反應級數反映了一個經由四中心過渡態的雙金屬自由基碳碳鍵活化反應機制。 / 在由銥催化的系統中，發現了Irᴵᴵᴵ(ttp)H在加氫過程中的促進作用。Irᴵᴵᴵ(ttp)H與碳碳鍵活化中間體的雙分子還原消除反應把加氫過程加快。根據估計，這個雙分子還原消除反應比碳碳鍵活化中間體的水解要快3倍。 / To, Ching Tat. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2015. / Includes bibliographical references. / Abstracts also in Chinese. / Title from PDF title page (viewed on 14, September, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 285-288. / by Joseph Francis Cocchetto. / Ph.D.